[TASK] Cleanup cache clearing

With change #75581 the backend toolbar cache handling the
"system" options are obsolete and can be deprecated.

Additionally, the label change is moved to an own label to
not clash with 7.6 and the now obsolete labels are deleted.

Change-Id: I666d73a97251beeddba78fba1940c0ea7fa29e58
Resolves: #75625
Related: #75581
Releases: master
Reviewed-on: https://review.typo3.org/47673


Reviewed-by: Helmut Hummel <helmut.hummel@typo3.org>
Reviewed-by: Benjamin Kott <info@bk2k.info>
Tested-by: Benjamin Kott <info@bk2k.info>
Reviewed-by: Frank Naegler <frank.naegler@typo3.org>
Tested-by: Frank Naegler <frank.naegler@typo3.org>